The five-minute tape confirms that Jerome Murdough, who officials have said was not checked on for at least four hours, had been dead for some time before he was discovered slumped at the foot of his bed with a pool of vomit and blood on the floor, said family lawyer Derek Sells.

Bronx prosecutors are investigating the death. A spokesman for the Department of Correction said he couldn't comment on pending litigation.

A spokesman for the Law Department said city lawyers hadn't yet received a copy of the family's lawsuit and will review it once it's filed. City lawyers turned over the tape and other documents to Sells in a stipulation reached last week to preserve investigative records, videotapes, logbooks and other evidence related to the Feb. 15 death.

Murdough "basically baked to death" in the overheated cell, a city official earlier told the AP, speaking on the condition of anonymity because the official wasn't permitted to discuss the case. An initial Department of Correction investigation disclosed in an unrelated federal lawsuit in April found Murdough's internal body temperature was 103 degrees and the cell was 101 degrees.

The medical examiner hasn't officially determined the cause and manner of death, but an investigator said he likely died of hyperthermia, according to the initial corrections investigation. Murdough suffered from bipolar disorder and schizophrenia, according to his family. He was on psychotropic drugs that experts say can make people more sensitive to heat.

The officer assigned to tour the mental observation unit where Murdough was housed abandoned her post 20 minutes before he was discovered, according to the investigation. The AP reported in May that jail guard had been disciplined four years earlier for doing the same thing.

Murdough was arrested a week before his death on a misdemeanor trespassing charge for sleeping in the stairwell of a public housing building. He was sent to Rikers after being unable to make a $2,500 bail.